France on Wednesday became the second European country to ratify the accord, after Hungary, and the first the Group of Seven advanced economies. The ratification was formally authorised by the French parliament last week.

The Paris Agreement aims to keep the rise in global temperature below 2C compared with pre-industrial times. It comes into force once 55 countries representing at least 55% of global emissions have joined it.

China, the world's top carbon emitter, said it intends to ratify the agreement before the G20 summit in China in September. The United States, the second-largest emitter, also announced its intention to ratify this year.